IT was a case of life imitat­ing art for “The Big Bang Theory” star Kaley Cuoco!

A source says Kaley’s role as a ready-to-wed fiancée on her new flick “The Wed­ding Ringer” prompted her beau to pro­pose.

The unlucky-in-love actress, 27, had been sporting a prop sparkler on and off the set of her new film, “The Wedding Ringer.” And an insider says it was a signal to her tennis pro boyfriend, Ryan Sweet­ing, that she was ready for the real thing.

“Kaley’s crazy about Ryan,” said a source. “She was wearing the fake bling all around hoping Ryan would get the hint – and he did!”

Kaley and Ryan have been seen together since early Au­gust, after her short-lived relationship with “Man of Steel” star Henry Cavill fizzled out. She was previously engaged to addiction specialist Josh “Lazie” Resnik, but that romance ended in February 2012.

Kaley secretly dat­ed her “Big Bang” co-star Johnny Ga­lecki for two years. And after that, she was in a relationship with Chris French from the band Annie Automatic.

Despite the big announcement, Kal­ey’s pals still hope she waits a while be­fore walking down the aisle.

Ryan, 26, earned just $23,900 playing tennis this year and is ranked 532 in the world.

And as The ENQUIRER reported in August, he’s also been busted on booze and drug charges in the past.

But none of that seems to matter to Kaley.

After Ryan pro­posed on Sept. 25, she tweeted: “Flying high, I could literally touch the sky with you…”